Gear case vent



R E B u H L M GEAR CASE VENT Filed May 11, 1965 INVENTOR T/MEFP Hus?ATTORNEY United States Patent Ofhce V 3,308,681 GEAR CASE VENT MortimerJ. Huber, 5901 W. Bald Eagle Blvd, St. Paul, Minn. 55110 Filed May 11,1965, Ser. No. 454,858 4 Claims. (Cl. 74-606) This invention relates toan improvement in gear case vent systems, and deals particularly with ameans of filling and venting a gear case used to connect a motor to adriven rotatable shaft.

Rotatable display signs are produced in considerable volume. These signsare normally mounted upon a vertical shaft, and are driven by anelectric motor. The motor is normally connected to the vertical shaftthrough a gear reduction unit. In view of the fact that signs of thetype in question are usually subjected to severe strain and to theaction of the elements, the gear cases must be ruggedly built and arenormally tightly sealed.

One of the difficulties which has been experienced lies in the fact thatthe oil within the gear cases tends to expand and contract on variationsin temperature and, accordingly, the casings must be provided with somesort of vent passage. This is not a particular problem as long as thegear cases are supported in a predetermined position. However, it isextremely desirable that the drive units be arranged so that they can bepositioned either above the sign in which case the shaft which supportsthe sign extends downwardly from the driven unit while in otherinstances the drive unit is supported beneath the sign with the shaftsupporting the sign extending upwardly. A vent opening in what wouldnormally be the top of the unit in one position would act as a drain ifthe drive unit were inverted.

It is also desirable to provide a filling passage through which the gearcase may be filled with oil. Such a filling opening could be providedwith a plug to close the opening when desired. However, from asimplicity standpoint, it is desirable to provide a filling openingwhich need not be closed.

An object of the present invention resides in the provision of aninvertible gear housing having a pair of passages incorporated therein,one of which may serve as a filling assage and the other of which mayserve as a vent passage. These passages are so arranged as to eliminatethe leakage of oil from the gear case whether the housing is mounted inupright or inverted position.

A feature of the present invention resides in the provision of a firstpassage which extends downwardly from the top surface of the gear caseto terminate in closely spaced relation to the bottom of the casing atwhich point it is connected by a horizontal passage to the interior ofthe gear casing level with the floor thereof. A second passage isprovided from the bottom of the casing to a point in closely spacedrelation to the top of the housing, and which is connected by ahorizontal passage to the interior of the casing at the top thereof.When the gear casing is mounted in upright position, the passageextending through the top of the casing forms a filling passage throughWhich fluid may flow to substantially fill the casing. The passageextending through the bottom of the casing serves as a vent passage fromthe upper portion of the casing interior. In filling the casing, thefluid may flow through the filling passage until the casing is virtuallyfull. At this time, the overflow of fluid will flow through the ventpassage and drain out. When the casing is mounted in inverted position,the passage which has served as the filling passage will serve as thevent passage, and the vent passage shall serve as the filling passage.

These and other objects and novel features of the present invention willbe more clearly and fully setforth in the following specification andclaims:

3,398,68l Faten'ted Mar. 14, 1967 In the drawings forming a part of thespecification;

FIGURE 1 is a diagrammatic view showing a sign supported on a verticalshaft above a drive unit.

FIGURE 2 is an elevational view showing a sign mounted upon a verticalshaft and driven by a drive unit supported above the sign.

FIGURE 3 is an elevational view of the drive unit.

FIGURE 4 is a top plan view of the drive unit.

FIGURE 5 is an end elevational view of one end of the drive unit.

FIGURE 6 is a vertical sectional view through a portion of the driveunit housing, the position of the section being indicated by the line6-6 of the FIGURE 4.

FIGURE 7 is a vertical sectional view through a portion of the gearcasing, the position of the section being indicated by the line 7-7 ofFIGURE 4.

FIGURE 8 is an enlarged plan view of the end portion of the lowersection of the gear casing, with the upper section removed.

While the present .drive unit is adaptable for use for many purposes,the construction is actually designed for use in conjunction with a signmounted for rotation about a vertical axis. FIGURE 1 of the drawingsdiscloses a sign 10 mounted upon a vertically arranged shaft 11.

In order to describe a reason for the present construction, FIGURES land 2 of the drawings are de signed to show signs'which are rotatableabout a vertical axis, one of which is driven by a drive unit locatedbeneath the sign, and the other of which is designed to support the signbeneath the drive unit. In one instance, the drive unit is in what maybe termed an upright position. In the other case, the drive unit ispositioned in an inverted position.

As indicated in FIGURE 1 of the drawings, the drive unit A is providedwith a driven shaft 11, an extension of which supports the sign 10 on avertical axis. The figure housing A is supported by a supporting plate12 which in turn is supported by a suitable frame not illustrated in thedrawings. An extension of the shaft 11 is supported in a verticalposition by the bearing 13 and acts to support the sign 10. A motor 14is connected to the under-surface of the gear housing A, and the motorshaft is connected to the driven shaft 11 by suitable gearing so as torotate the sign at a speed substantially less than the speed ofrotattion of the motor.

FIGURE 2 shows a similar structure in inverted position, the supportingplate 12 being located above the rotatable sign 15 and the shaft 11extending downwardly therefrom. While the shaft 11 is normallyrelatively short, the shaft 11' merely forms an extension thereof.

As indicated in this figure, the gear case A is above the support 12 andthe motor 14 extends upwardly therefrom, the bearing 13 being on theother side of the supporting plate 12.

As is diagrammatically illustrated in FIGURE 4 0f the drawings, theshaft 16 of the motor 14 extends into the housing A and is connected bysuitable gears indicated at 18 in broken lines to the driven shaft 11.As

the particular gear arrangement employed is unimportant of theperipheral wall 23 are arranged in edge abutting relation, and a gasket24 is interposed between the two sections to form a seal. The sectionsare held together by suitable means such as by cap screws 25 extendingthrough the peripheral wall 23 of the upper section 21 and are threadedinto threaded sockets in the upstanding wall 20 of the lower section 19.Portions of the walls 23 and 23' may be thickened to accommodate the capscrews and the sockets.

While the section 17 has been indicated and as the lower section and thesection 21 as the upper section, it should be understood that the gearcase is designed to function equally well in inverted position as longas the driven shaft 11 is substantially vertical. The problem involvedis in providing a means of substantially filling the gear case withlubricating oil, of knowing when the gear case is filled, and inproviding a vent which is opened to atmosphere so that any expansion ofthe oil will not develop pressure within the gear case. This isaccomplished in the manner best illustrated in FIGURES 4 through 8 ofthe drawings.

As indicated in FIGURE 8 of the drawings, and inwardly extending boss 26is provided in the casing wall 20, and a similar boss 27 is provided inthe wall 23 of the upper section 21. The purposes of the bosses 26 and27 is merely to increase the'thickness of a portion of the peripheralwall of the gear case and to provide the necessary space for theapertures. As indicated in FIGURE 6, a hole 29 is drilled downwardlythrough the top closure plate 22 through the boss 27 and a similarpassage '30 in alignment with the passage 29 is drilled into the boss 26in the lower section 19. The passage 30 terminates about level with theupper surface 31 of the bottom closure plate 19. A substantiallyhorizontal passage 32 extends through the wall of the bOSs 26 and intothe interior of the gear case as is indicated in FIGURE 8 of thedrawings. In view of the fact that the passages 29, 30 and 32, arenormally formed by drilling, a relatively large diameter aperture 33extends from the vertical passage 30 to the exterior of the gear case.The aperture 33 is internally threaded to accommodate a screw plug 34which closes and seals this aperture 33.

As is also indicated in FIGURES 6 and 7 of the drawings, a passage 35extends upwardly from the undersurface 36 of the bottom closure plate 19through the boss 26, and a communicating passage 37 is provided in theboss 27 which terminates substantially on the level of the under-surface39 of the top closure plate 22. A substantially horizontal passage 40extends through the boss 27 from the passage 37 to the interior of thegear case to provide communication therewith. As a matter of expediency,a concentric larger diameter aperture 41 is drilled through the outerwall 23 of the upper section 21. This aperture 41 being tapped toaccommodate a plug 42 to seal the hole 41 after the passage 40 has beendrilled.

When the gear case is to be used, it is first normally substantiallyfilled with lubricating oil. This is done by introducing oil through thealigned vertical passages 23 and 30, the oil flowing through thehorizontal passage 32 into the interior of the gear housing. As thelubricating oil enters the gear case, it displaces air which is ventedto the horizontal passage 40 and the aligned passages 37 and 35. Whenthe level of the oil in the gear case reaches the level of the passage40, any additional oil added will drain through this passage 40 and thevertical passages 37, 35 providing a clear indication that the gearcaseis full. In the event the oil expands, the excess oil may also drainthrough the same openings.

In the event the gear case A is used in what has been termed theinverted position shown in FIGURE 2, the passages described operate in asimilar manner except that the aligned passages 35, 37 and thehorizontal passage 40 form the filling passages while the horizontalpassage 32 and the vertical passages 30, 29 form the overflow and 4.vent passages. Thus, the vent system operates in the same mannerregardless of which of the two positions is employed.

In the past some difficulty has been experienced in provided fillingopenings, vent openings, and drain openings which comprised a fool-proofcombination. Normally, it is necessary to have a filling opening on boththe top and bottom sides of the housing, a vent opening on both of thesesides of the housing, and a drain opening on each side of the housing.If, in installing the gear case, the proper holes were not plugged orleft unplugged, the device would not function properly. With the presentarrangement, there is no chance of air, as only one passage may be usedto till the gear case, and the other passage automatically functions asan overflow pipe as well as a vent. Thus, while the arrangement issimple, it eliminates the danger of costly errors due to improperinstallation procedures.

In accordance with the patent statutes, the principles of constructionand operation of this improvement in Gear Case Vent have been described,and while an endeavor has been made to set forth the best embodimentthereof, it should be understood that changesmay be made within thescope of the following claims without departing from the spirit of theinvention.

I claim:

1. A gear case vent system including;

a hollow housing,

a motor secured to said housing and having a motor shaft extending intosaid housing,

a driven shaft extending from said housing and supported thereby,

a series of gears supported within said housing connecting said motorshaft to said driven shaft,

said housing including a top panel, a bottom panel,

and a peripheral connecting wall portion,

a substantially vertical passage extending from the upper surface of thetop panel downwardly through the peripheral wall portion to a pointspaced from the under surface of the bottom panel and communicating atits lower end with the interior of the gear housing adjoining the uppersurface of the bottom panel, and

a second substantially vertical passage extending from the under surfaceof the bottom panel upwardly through the peripheral wall portion to apoint spaced from the upper surface of the top panel and communicatingat its upper end with the interior of the housing adjoining the undersurface of the top panel, whereby when oil is directed into the housingthrough said first mentioned vertical passage, said second verticalpassage functions as an overflow and a vent for the interior of thehousing. a

2. A gear case vent system for use in conjunction with an invertablegear case, the gear case comprising a hollow housing having generallyparallel top and bottom walls and peripheral connecting side Walls, adrive means connected to said housing and having a drive shaft extendinginto said housing, a driven shaft supported by said housing andextending therefrom, and gear means connecting said shafts, said ventsystem incuding:

a filling passage open to atmosphere at the top of said housing andcommunicating with the interior of said housing at the bottom thereof,

a vent passage open to atmosphere at the bottom of said housing andcommunicating with the interior of said housing at the top thereof,

whereby when said housing is inverted, said filling passage becomes avent passage and said first mentioned vent passage becomes a fillingpassage.

3. The structure of claim. 2 and in which said vent and filling passagesextend through the peripheral wall of said housing.

5 6 4. The structure of claim 2 and in which said housing 2,237,958 4/1941 Hansen et a1. 74606 is formed of two sections in edge abuttingrelation. 2,517,913 8/1950 Nickle 74606 X References Cited by theExaminer UNITED STATES PATENTS MOrgan X H. ASSlStallt Examlner.

5 LAVERNE D. GEIGER, Primary Examiner.

1. A GEAR CASE VENT SYSTEM INCLUDING; A HOLLOW HOUSING, A MOTOR SECUREDTO SAID HOUSING AND HAVING A MOTOR SHAFT EXTENDING INTO SAID HOUSING, ADRIVEN SHAFT EXTENDING FROM SAID HOUSING AND SUPPORTED THEREBY, A SERIESOF GEARS SUPPORTED WITHIN SAID HOUSING CONNECTING SAID MOTOR SHAFT TOSAID DRIVEN SHAFT, SAID HOUSING INCLUDING A TOP PANEL, A BOTTOM PANEL,AND A PERIPHERAL CONNECTING WALL PORTION, A SUBSTANTIALLY VERTICALPASSAGE EXTENDING FROM THE UPPER SURFACE OF THE TOP PANEL DOWNWARDLYTHROUGH THE PERIPHERAL WALL PORTION TO A POINT SPACED FROM THE UNDERSURFACE OF THE BOTTOM PANEL AND COMMUNICATING AT ITS LOWER END WITH THEINTERIOR OF THE GEAR HOUSING ADJOINING THE UPPER SURFACE OF THE BOTTOMPANEL, AND A SECOND SUBSTANTIALLY VERTICAL PASSAGE EXTENDING FROM THEUNDER SURFACE OF THE BOTTOM PANEL UPWARDLY THROUGH THE PERIPHERAL WALLPORTION TO A POINT SPACED FROM THE UPPER SURFACE OF THE TOP PANEL ANDCOMMUNICATING AT ITS UPPER END WITH THE INTERIOR OF THE HOUSINGADJOINING THE UNDER SURFACE OF THE TOP PANEL, WHEREBY WHEN OIL ISDIRECTED INTO THE HOUSING THROUGH SAID FIRST MENTIONED VERTICAL PASSAGE,SAID SECOND VERTICAL PASSAGE FUNCTIONS AS AN OVERFLOW AND A VENT FOR THEINTERIOR OF THE HOUSING.